An automatic transmission controls hydraulic pressure by operating at least one actuator according to a driving state, such as a vehicle speed and a throttle opening, in order to perform shifting to a target shift speed, or ratio.
In a case in which the shifting to the target shift speed is performed, an automatic transmission may have an off-going, or first, friction element that changes from an engaged state to a released state and an on-coming, or second, friction element that changes from a released state to an engaged state. Releasing, or actuating, an off-going friction element and engaging, or actuating, an on-coming friction element may be realized, or implemented, by controlling hydraulic pressure supplied to respective elements.
In addition, the control of the hydraulic pressure supplied to the off-going and on-coming friction elements may be performed by operating a control duty and controlling the actuator according to the control duty.
An electric hydraulic pump may be applied to the automatic transmission and may operate an off-going solenoid to release the off-going friction element (e.g., an off-going clutch) or operate the on-coming solenoid to engage the on-coming friction element (e.g., an on-coming clutch) when a gear is shifted to any gear shift stage in a state in which a pump is driven by an operation of a motor, thereby executing the shifting.
However, when producing an automatic transmission single part, or single parts of the automatic transmission, if a deviation depending on each single part is not considered, an adverse impact may be generated when a gear shifting operation is performed. For example, in the case of the solenoid, the solenoid has a deviation of a discharge rate depending on each part made. In the case of the clutch, a charge time of the oil may be different depending on each part made.
If the collective control is performed in a transmission control unit (TCU) without the accounting for difference of the dynamic characteristics of the automatic transmission single parts, the impact may be generated during a gear shifting operation.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.